Ribonuclease P/MRP 21kDa Subunit (RPP21)

RPP21 is a protein subunit of nuclear ribonuclease P, which processes the 5-prime leader sequence of precursor tRNAs .The deduced RPP21 protein contains 154 amino acids and has a calculated molecular mass of 17.6 kD. It has a distinctive cysteine arrangement spanning amino acids 62 to 95 that includes 2 CXXC thioredoxin (TXN) box motifs. The RPP21I variant retains intron 1 and exhibits alternative splicing of exon 4. These changes introduce 23 additional codons and alter the downstream ORF of RPP21, respectively.

The deduced 167-amino acid RPP21I protein has a calculated molecular mass of 19.0 kD. It has an arginine- and proline-rich region, followed by the cysteine arrangement found in RPP21.